MgH₂ has become a hot spot in the research of hydrogen storage materials, due to its high theoretical hydrogen storage capacity. However, the poor kinetics and thermodynamic properties of hydrogen absorption and desorption seriously hinder the development of this material. Ti-based materials can lead to good effects in terms of reducing the temperature of MgH₂ in hydrogen absorption and desorption. MXene is a novel two-dimensional transition metal carbide or carbonitride similar in structure to graphene. Ti₃C₂ is one of the earliest and most widely used MXenes. Single-layer Ti₃C₂ can only exist in solution; in comparison, multilayer Ti₃C₂ (ML-Ti₃C₂) also exists as a solid powder. Thus, ML-Ti₃C₂ can be easily composited with MgH₂. The MgH₂+ML-Ti₃C₂ composite hydrogen storage system was successfully synthesized by ball milling. The experimental results show that the initial desorption temperature of MgH₂-6 wt.% ML-Ti₃C₂ is reduced to 142 °C with a capacity of 6.56 wt.%. The E_a of hydrogen desorption in the MgH₂-6 wt.% ML-Ti₃C₂ hydrogen storage system is approximately 99 kJ/mol, which is 35.3% lower than that of pristine MgH₂. The enhancement of kinetics in hydrogen absorption and desorption by ML-Ti₃C₂ can be attributed to two synergistic effects: one is that Ti facilitates the easier dissociation or recombination of hydrogen molecules, while the other is that electron transfer generated by multivalent Ti promotes the easier conversion of hydrogen. These findings help to guide the hydrogen storage properties of metal hydrides doped with MXene.

The special surface appearance of complex surfaces restricts the coating film quality of spraying. The study of the atomization and film formation characteristics of typical complex surfaces, as well as the spraying mechanism, is essential for planning the spraying robotic trajectory and improving the spraying efficiency. In this paper, modeling and characteristics of the atomization and film formation process, based on CFD numerical simulations in previous studies, are systematically reviewed, focusing especially on airless spraying. In addition, the advantages and disadvantages of the existing research from the perspective of numerical models and methods are discussed. Finally, a further research direction for spraying on complex surface is prospected. Overall, a comprehensive and up-to-date review of spray atomization and film formation characteristics is considered valuable to practitioners and researchers in these fields, and will facilitate the further application of robotic spraying in the mechanical, automotive, marine, aerospace, petrochemical and other industries.

Based on the computational fluid dynamics (CFD) theory, this paper proposes a film formation model and a numerical simulation method that can be used in thickness prediction of airless spraying robots. The spraying flow field and the film formation process in the airless spraying process were simulated by the Eulerian–Eulerian approach, and the airless spraying film formation model including the paint expansion model and the wall hitting model was established. To verify the correctness of the model, numerical simulations of static spraying and dynamic spraying were carried out on the plane and arc surfaces. The simulation results showed that the width of the spraying flow field on the far wall increased linearly with the longitudinal distance in the major-axis direction. The busbar spraying on the outer surface of the arc surface showed the similar characteristics to the plane in the major-axis direction. Besides, the annular spraying was similar to the plane spraying in the minor-axis direction, but the inner surface spraying was completely opposite. When spraying the outer surface, the film thickness increased with the increase of the inner diameter but was smaller than that of the plane spraying, while the inner surface spraying was completely opposite. In the spraying experiment, the plane dynamic spraying and the arc plane inner and outer surface translation spraying were selected for verification. The experimental results were in good agreement with the simulation results, indicating that the film formation model of airless spraying established in this paper is basically correct. As a result, this model can be used for thickness prediction of spraying robots.

Near-nozzle atomization characteristics in air-assisted spraying were investigated through a novel 3D transient model integrating Volume-of-Fluid and Large Eddy Simulation (VOF-DPM) methods, with experimental validation of droplet distributions (Malvern analyzer) and coating thickness profiles. Key findings reveal that (1) the spray field stabilizes within 30 mm downstream, achieving 80% atomization efficiency (droplets ≤ 100 μm) at 27.5 mm axial distance; (2) radial momentum originates dually from fan-shaped airflow (max 595 m/s) and transverse motion induced by central atomizing air entrainment—a previously unreported mechanism; (3) paint loading delays flow stabilization to 2.5 ms (vs. 0.7 ms for gas-only flow) while reducing peak axial velocity by 18%–22% due to gas–liquid momentum exchange; (4) auxiliary and fan airflows synergistically constrain dispersion, forming elliptical sprays with characteristic cone angles of 61.7° (short axis) and 99.1° (long axis). Significantly, surface tension plays a dual role in inhibiting droplet atomization while promoting ligament pinch-off at 8.1 mm breakup length. These results provide the first quantitative characterization of gas–liquid interactions in near-nozzle regions, enabling precise parameter control for enhanced coating uniformity on complex surfaces.

This paper presents an acoustic emission (AE) detection method for refined oil storage tanks which is aimed towards specialized places such as oil storage tanks with high explosion-proof requirements, such as cave oil tanks and buried oil tanks. The method utilizes an explosion-proof acoustic emission instrument to detect the floor of a refined oil storage tank. By calculating the time difference between the defective acoustic signal and the speed of acoustic wave transmission, a mathematical model is constructed to analyze the detected signals. An independent channel AE detection system is designed, which can store the collected data in a piece of independent explosion-proof equipment, and can analyze and process the data in a safe area after the detection, solving the problems of a short signal acquisition distance and the weak safety protection applied to traditional AE instruments. A location analysis of the AE sources is conducted on the bottom plate of the tank, evaluating its corrosion condition accurately. The consistency between the evaluation and subsequent open-tank tests confirms that using AE technology effectively captures corrosion signals from oil storage tanks’ bottoms. The feasibility of carrying out online inspection under the condition of oil storage in vertical steel oil tanks was verified through a comparison with open inspections, which provided a guide for determining the inspection target and opening order of large-scale oil tanks.

Painting a V-shaped surface, which is widely found in various facilities and equipment, often results in poor coating quality, which may be caused by an insufficient understanding of film-forming characteristics and mechanism. In this study, computational fluid dynamic (CFD) simulations were carried out for in-depth research on the film-forming characteristics and mechanism of painting V-shaped surfaces. The mathematical model of film formation was established with the Euler–Euler method, and the unstructured grids and adaptive-mesh refinement were adopted to discretize the computational domain. By solving the model, the coating thickness distribution law and flow-field characteristics of spraying a V-shaped surface were obtained. When painting a V-shaped surface with an angle less than 180°, the coating thickness distribution appeared as two peaks, instead of the single peak that appeared when painting a flat wall. As the V-shaped angle decreased, the coating thickness became thinner. The peak position gradually shifted to both sides, and the thickness distribution became wider. Analysis of the spray flow-field characteristics revealed the thickness distribution mechanism, by whichthe geometric characteristics of the V-shaped surface changed the near-wall distribution of the flow field. When the V-shaped angle decreased, the pressure peak at the center of the V-shaped surface and the eccentric pressure peaks that formed on both sides increased. The near-wall paint fluid was confined between the central pressure peak and the off-center pressure peak, resulting in paint droplets depositing between the pressure peaks and double-peak distribution of the coating thickness forming on the V-shaped surface. The spraying experiments verified the correctness of the numerical simulations, film-forming characteristics, and corresponding mechanism, which are of great significance for efficient and high-quality spraying on V-shaped surfaces.